Vacuum frying has conventionally been used as a method for obtaining dried foods for packaging. In vacuum frying, the starting food, such as sliced vegetables, after being immersed in a sugar solution for 6 to 12 hours, is fried in oil in an autoclave, and then drained free of excess oil. This method has low production efficiency because it requires a long time for immersion and frying, resulting in high production cost. Furthermore, an undesirably large amount, up to 40%, of oil is left in the fried product which causes deterioration in quality during long-term storage (oxidation of oil) and affects the smell and taste of the stored product. Furthermore, vacuum fried foods cannot be powdered at normal temperature due to the large content of residual oil. Finally, the original color and taste of the starting food are impaired as well.
It would obviously be desirable to produce dried food products which do not suffer the above defects of the prior art. Thus, a need exists for a method for obtaining high quality dehydrated food products which can be stored for relatively long periods without deterioration in properties, can be produced in a far shorter processing time, are greatly reduced in the amount of residual oil, remarkably retain the natural color and taste of the starting raw material, and are characterized by such dryness and crispness that they are readily adapted for pulverization into finely divided form such as flour or the like.